Food and bioenergy: reviewing the potential of dual‐purpose wheat crops

Abstract

Within the bioenergy debate, the ‘food vs. fuel’ controversy quickly replaced enthusiasm for biofuels derived from first‐generation feedstocks. Second‐generation biofuels offer an opportunity to produce fuels from dedicated energy crops, waste materials or coproducts such as cereal straw. Wheat represents one of the most widely grown arable crops around the world, with wheat straw, a potential source of biofuel feedstock. Wheat straw currently has limited economic value; hence, wheat cultivars have been bred for increased grain yield; however, with the development of second‐generation biofuel production, utilization of straw biomass provides the potential for ‘food and fuel’. Reviewing the evidence for the development of dual‐purpose wheat cultivars optimized for food grain and straw biomass production, we present a holistic assessment of a potential ideotype for a dual‐purpose cultivar (DPC). An ideal DPC would be characterized by high grain and straw yields, high straw digestibility (i.e. biofuel yield potential) and good lodging resistance. Considerable variation in these traits exists among current wheat cultivars, facilitating the selection of improved individual traits; however, increasing straw yield and digestibility could potentially have negative trade‐off impacts on grain yield and lodging resistance, reducing the feasibility of a single ideotype. Adoption of alternative management practices could potentially increase straw yield and digestibility, albeit these practices are also associated with potential trade‐offs among cultivar traits. Benefits from using DPCs include reduced logistics costs along the biofuel feedstock supply chain, but practical barriers to differential pricing for straw digestibility traits are likely to reduce the financial incentive to farmers for growing higher ‘biofuel‐quality’ straw cultivars. Further research is required to explore the relationships among the ideotype traits to quantify potential DPC benefits; this will help to determine whether stakeholders along the bioenergy feedstock supply chain will invest in the development of DPCs that provide food and fuel potential.

Addressing the Role of Landraces in the Sustainability of Mediterranean Agroecosystems

“…However, our results showed no significant differences in grain yield, and therefore the higher straw biomass production was the main factor responsible for the higher CDM of landraces. Other studies have reported higher straw biomass production of landraces [28], which can have potential sustainability benefits. Cereal straw mulching has been proven to effectively reduce soil erosion and increase soil quality, biological activity, and soil aggregate stability [29] under Mediterranean rainfed conditions.…”

Structural Analysis of Alkaline Pretreated Rice Straw for Ethanol Production

“…This step is expected to increase liquid volume in the system, thus improving ethanol production rate by yeast [35,36]. In this study, the prehydrolysis times of 3,6, and 16 h were tested to find the suitable time for inoculating yeasts, and their ethanol yields were compared with that by the SSF alone ( Figure 6). The initial glucose concentrations increased according to increasing prehydrolysis time.…”

“…Rice straw (RS) is a by-product after rice grain collection. This lignocellulosic waste has been promoted as a potential feedstock for ethanol production in Thailand and other Asian countries due to its ready availability, abundance, and the fact that it is nonfood [3,4]. This material is an excellent source of sugars for microbial fermentation owing to the presence of carbohydrates that are concentrated in the cell walls [5].…”

Wheat straw availability for bioenergy in England

“…In addition to understanding farmers' willingness to supply straw from current production levels, farmers may also adjust their straw production practices in response to potentially higher straw prices resulting from changes in the straw market. Given that modern plant breeding and agronomic practice has led to production of shorter straw in cereal crops, Townsend et al (2015) reviewed the concept of a dual-purpose wheat cultivar that was optimised for grain for feed or food markets and straw for the biofuel market. Management practices that could influence straw yield were identified; however, given the lack of scientific focus towards increased straw production, there is little research to support these practices.…”